With the increasing popularity of Internet commerce and network centric computing, businesses and other entities are becoming more and more reliant on information. Protecting critical data from loss due to system crashes, virus attacks and the like is therefore of primary importance. A well designed data protection program will generally have the ability to (i) instantly re-store data in the event of a disaster to enabled continued computing operations; (ii) re-store data over an extended period of time (hours or days) without disrupting normal computing operations; and (iii) archive copies of data that are retrieved infrequently and with little urgency. Tape drives have long been a choice for storing archival back up data in information systems.
Historically many such tape drives have used data compression to maximize the amount of data that can be stored on the tape. Tape, however, is a relatively slow and inefficient storage medium. Consequently emulated “tape” drives that use arrays of hard drives have become more popular recently. These emulated tape drives often rely on data compression to enable the storage of more data. The problem with current emulated tape drives is that the data compression is performed “on the fly” during the backup. In other words, compression occurs in the critical path of the down loading of data, thereby impeding performance. The designers of emulated tape drive systems have therefore relied on expensive, high speed, hardware data compression solutions to achieve an acceptable level of performance. The use of slower, less expensive software compression algorithms have not been a viable option in the past because of a lack of acceptable performance.
An emulated backup tape drive that stores non-compressed data during backup operations and then afterwards when the drive is idle, retrieves, compresses and then re-stores the data to reclaim space on the storage medium of the drive is therefore needed.